This invention relates to a composition containing oxygen, lead, magnesium and aluminum and to the use of such composition in the oxidative synthesis of stilbene from toluene and the demethylation of toluene to produce benzene.
Stilbene, because of its unsaturated character, is very reactive and may be employed in various ogranic syntheses. Derivatives of stilbene are useful in the production of products which may be used in the manufacture of dyes, paints and resins. It is also useful in optical brighteners, in pharmaceuticals and as an organic intermediate.
Stilbene has been synthesized by dehydrogenation of bibenzyl; by dehydrogenation of 1,2-bis(3-cyclo-hexe-1-yl) ethylene (U.S. Pat. No. 3,387,050); and by reacting a benzyl mercaptan with a sulfactive catalyst, for example, molybdenum disulfide and copper sulfide (U.S. Pat. No. 2,645,671). Stilbene and halostilbenes have been synthesized by the iodative dehydrocoupling of toluene and halogen substituted toluenes with elemental iodine and molten lithium iodide at toluene conversions of 10-30% (U.S. Pat. No. 3,409,680).
Dehydrocoupling of toluene by the reaction with lead oxide to form stilbene has been reported by Behr and Van Dorp, Chem. Ber. 6, 753 (1873) and Lorenz, Chem. Ber. 7, 1096 (1874). In this reported work, stilbene is obtained by conveying toluene over lead oxide maintained at or about at a dark red glow. A more recent disclosure of the toluene lead oxide reaction is given in U.S. Pat. No. 3,494,956. In Example 9 of this patent, it is reported that a mixture of toluene and oxygen passed over heated lead oxide produces bibenzyl.
Benzene is a valuable hydrocarbon having many uses. A major use today is in the production of styrene by ethylene alkylation to form ethylbenzene followed by dehydrogenation to form styrene. Styrene finds use as a monomer in the polymer field.